Unobtrusive cardio-respiratory monitoring based on microwave Doppler radar

Detection and monitoring of vital signs is an important task namely in rescue missions. It requires the use of biomedical devices that permit to acquire the vital signs information in an unobtrusive and even remote way, which represents an important challenge in the design and implementation of systems for vital signs detection and monitoring. At the same time, the usage of non-mechanical and non-electrical contact systems for vital signs monitoring in home-tele-healthcare applications increases the user comfort and significantly reduces the stress associated with measurement procedures. The article presents the design and implementation of an unobtrusive cardio-respiratory assessment module based on microwave Doppler radar and dual channel conditioning circuit including 4th order analog active filters and programmable gain amplifiers. The module testing was done using an automated measurement system based on a PXI acquisition platform and LabVIEW software. An advanced digital signal processing software component expressed by wavelet algorithms for denoising, detrending and peak-detection was designed and implemented in order to extract information such as heart rate, heart rate variability and respiration rate. A practical approach concerning the system performance is included in the paper.